Between 2002-2012, the NIDDK-sponsored prospective Chronic Renal Insufficiency Cohort (CRIC) Study enrolled 3939 adults with chronic kidney disease (CKD) at 7 Clinical Centers to address overarching goals of identifying risk factors for CKD progression and clarifying the relationship between kidney dysfunction and the risks of subclinical and clinical cardiovascular events, death, and resource utilization through an initial 10-year follow-up of CRIC-Phase 1. Phase 2 of CRIC, extended follow-up through April 30, 2013. This application is submitted in response to RFA-DK-12-508, Limited Competition: Continuation of the Chronic Renal Insufficiency Cohort (CRIC) Study (U01), on behalf of the University of Pennsylvania (Penn) Clinical Center. In Phases 1 and 2 of CRIC, the Penn was a model site that exceeded its recruitment goal, achieved high follow-up rates and outstanding data quality, and that contributed actively to study-wide governance and implementation. In Phase 3, the Penn clinical center has the following specific aims: 1. To re-enroll a high percentage of CRIC Phase 1 participants into Phase 3 of CRIC 2. To enroll an additional 214 participants into Phase 3 of CRIC 3. To collect exposure and outcome data per the CRIC Phase 3 protocol 4. To maintain high levels of retention in the study 5. To investigate self reported clinical events and obtain supporting medical records and documentation. 6. To enter data and process/ship biological specimens. 7. To implement local quality assurance and quality control procedures as a means to obtain standardized, high quality measurements 8. To monitor data collection, data entry, and follow-up rates 9. To participate in governance and oversight of CRIC through study wide subcommittees and activities 10. To publish and present findings from the CRIC Study 11. To promote and support the conduct of ancillary studies in CRIC, including collaboration with the broader nephrology research community. We look forward to the opportunity to continue participation in this unique and important study.